import 'dart:math' as math;

import 'package:flutter/material.dart';

import '../../utils/Colors.dart';
import 'ScenePainter.dart';

/// A painted landscape that stands in for photography: sky, a low sun, three
/// ridges and an oversized figure glyph standing in front of them. The [seed]
/// reshapes the ridges and moves the sun, so two routines of the same kind
/// never wear the identical picture.
class SceneArt extends StatelessWidget {
  /// sky top, horizon, sun, far ridge, mid ridge, near ridge, ember.
  final List<Color> palette;

  final int seed;

  /// The glyph standing in the scene — the kind's icon, usually.
  final IconData? figure;

  /// Figure size as a fraction of the shorter side.
  final double figureScale;

  final Alignment figureAlignment;

  /// Darkens the lower half so white type laid over it stays legible.
  final bool shade;

  const SceneArt({
    super.key,
    required this.palette,
    this.seed = 0,
    this.figure,
    this.figureScale = 0.5,
    this.figureAlignment = const Alignment(0.35, 0.15),
    this.shade = false,
  });

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(
      builder: (BuildContext context, BoxConstraints constraints) {
        final double shortest = math.min(
          constraints.maxWidth.isFinite ? constraints.maxWidth : 200,
          constraints.maxHeight.isFinite ? constraints.maxHeight : 200,
        );
        final double glyph = shortest * figureScale;

        return RepaintBoundary(
          child: Stack(
            fit: StackFit.expand,
            children: [
              CustomPaint(painter: ScenePainter(palette, seed)),
              if (figure != null)
                Align(
                  alignment: figureAlignment,
                  child: SizedBox(
                    width: glyph * 1.6,
                    height: glyph * 1.6,
                    child: Stack(
                      alignment: Alignment.center,
                      children: [
                        // The ember halo behind the figure — the reference's
                        // orange gi, reduced to light.
                        Container(
                          width: glyph * 1.5,
                          height: glyph * 1.5,
                          decoration: BoxDecoration(
                            shape: BoxShape.circle,
                            gradient: RadialGradient(
                              colors: <Color>[
                                palette[6].withValues(alpha: 0.45),
                                palette[6].withValues(alpha: 0.0),
                              ],
                            ),
                          ),
                        ),
                        Icon(
                          figure,
                          size: glyph,
                          color: colorWhite.withValues(alpha: 0.96),
                          shadows: <Shadow>[
                            Shadow(
                              color: palette[5].withValues(alpha: 0.55),
                              blurRadius: glyph * 0.22,
                              offset: Offset(0, glyph * 0.08),
                            ),
                          ],
                        ),
                      ],
                    ),
                  ),
                ),
              if (shade)
                DecoratedBox(
                  decoration: BoxDecoration(
                    gradient: LinearGradient(
                      begin: Alignment.topCenter,
                      end: Alignment.bottomCenter,
                      stops: const <double>[0.35, 1.0],
                      colors: <Color>[
                        colorBlack.withValues(alpha: 0.0),
                        colorBlack.withValues(alpha: 0.55),
                      ],
                    ),
                  ),
                ),
            ],
          ),
        );
      },
    );
  }
}